The invention relates to an apparatus for universal water treatment with cylindrical housing and rotating ring-basket, in which the housing is provided with untreated water inlet and purified water outlet stubs and the rotating filter basket contains back washing chamber, wherein said apparatus is continuously regenerated.
It is well-known that the substances floating in the water are removed during the filtering process. For this purpose traditionally sand filters have been used, the operation of which is essentially similar to the filtration taking place in the nature. However the fine grained layer in the water filters become polluted after a while, thus its regeneration is necessary.
The regeneration is carried out with clean water in counterflow to the filtration and during this process in given case the filter bed is loosened with air, or other gaseous medium.
The regeneration can be carried out only by interruption of the filtering process. Accordingly continuous filtration can be carried out only by use of several separate filtering apparatuses and during regeneration of one of the filtering apparatuses the filtration is carried out with the other or several other apparatuses.
However the generally decreasing filtering rate caused by pollution, and the thereby diminishing specific throughput require fairly large size filtering apparatuses, which will considerably increase the cost of filtering process.
Further difficulty is caused by the fact, that in order to increase the filtering efficiency, several filter beds are used whenever necessary. Furtuermore, in order to meet the different water treatment requirements, in addition to the removal of the floating solid impurities, chemical filtration too, such as acid-, gas-, iron-, nitrogen- and/or phosphorus-, heavy metal, salt-extraction, deodorization, etc. may be carried out as well. In this way, the simple filtering process is combined generally with other water treatment processes, which however necessitate the coonstruction of further filtering and treating vessels, which increase the cost of the already expensive intermittently operating filtering technology, Moreover the technology itself too becomes very complicated, since in order to ensure the intermittent operation, several coagulating or chemical-conditioning tanks, furthermore filters of different filter materials and grain size are necessary.
In order to reduce the above difficulties, filtering apparatuses were constructed for continuous purification. Known is for instance such apparatus fitted with wire spool, in which slowly rotating nozzle is used for washing over the filter element.
Another system comprises a scraper fitted into the gaps between the filter discs, combing out the accumulated impurities.
In continuously operating filter apparatuses, the separated impurity passes into a collecting space, from where it is periodically removed.
The disadvantage of above solutions lies first of all in that the extent of filtration is restricted by the gap size of the wire spools and filter discs.
Similar is the operation of the filter apparatuses fitted with continuously regenerating sieve cloth, or with different porous materials. Known are also fitter apparatuses provided with replaceable filter inserts and cartridges.
Such continuously flushing water filtering apparatus also exists, which has a cylindrical housing with rotating filter basket carried on sealed bearing and provided with untreated water inlet stub in the centre of the housing as well as purified water outlet stub reaching into the bottom part of the housing, the filter basket is closed on the top sealed and fitting into the hole of the outlet stub. The jacket of the filter basked is fitted with filter elements, while a cavity is formed on the inner wall of the housing fitting to the filter basket along a plane perpendicular to the inlet and outlet stubs, and the outlet hole passing through the wall of the housing is leading into the cavity. Such apparatuses are described in the Hungarian Pat. No. 172 006. Accordingly the filter elements are prisms retaining the filter medium, the prisms are formed by plate the two opposite sides of which are perforated, or by sieve cloth, which prisms have a mounting flange fitting to the filter basket. In a preferred embodiment the outer side of the filter basket is curved according to the radius of the filter basket. The filter medium in the filter basket mey be sand, crushed quartz, active carbon, crushed porcelain fragments or their optional mixture.
This apparatus ensures the filtering of the floating solids of the water, which has a small size, low cost of production and continuous operation, but it does not allow the simultaneous use of the filter elements of different quality and chemical filtration, thus it gives water purity corresponding only to industrial water quality.